1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and an apparatus for detecting a radio signal.
2. Related Art
Recently, services that require ultrahigh speed wireless communications such as wireless Internet are rapidly increasing. Therefore, researches on communication techniques capable of guaranteeing the ultrahigh speed wireless communications are actively performed.
In particular, researches on efficiently using resources such as time, frequency, and space for a plurality of users are actively performed. However, since the frequency resource may be used only by a user authorized to use the corresponding frequency, when an authorized business does not use the corresponding frequency band, no one uses the corresponding frequency resource so that the frequency resource is wasted.
Therefore, recently, in order to reduce such waste and to efficiently make temporal and spatial use of the frequency resource, a cognitive radio technology of finding out a frequency band that is not used to perform communications is spotlighted. In accordance with the cognitive radio technology, the temporally and spatially empty frequency band is used so that the efficiency of use of the frequency resource may be maximized.
Recently, as the federal communication commission (FCC) revises regulation so that the cognitive radio technology may be used in a TV frequency band, an environment for applying the cognitive radio technology is created and standardization of the cognitive radio technology such as IEEE 802.22 is being performed.
On the other hand, in order for an unauthorized user to use the temporally and spatially empty frequency band, a frequency detecting technology or a signal detecting technology is important. The detecting technologies suggested until now require complicated operations so that operation complexity is high.